Grimlock hears her taunts, but does not see her, nor does he see the fire ball really before its too late.

Unfortunately plain fire is something that Grimlock has little vulnerability to. His metal hide repels the spell with no effort, and he whips around in the direction it came from to squint angrily.

"Hmmm?!? Who challenge me Grimlock?! Dinobot?? Me Grimlock love fight, make big mess! You no tell me Grimlock what do!"

He roars defiantly at the sky, a horrible screeching metal sound mixed with that stock noise of the t rex from jurassic park, just to emphasize that he means business.